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      <h1 class="p_Heading1" style="page-break-after: avoid;"><span class="f_Heading1">Rack-Pinion Steering Model</span></h1>

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<p class="p_Normal">Starting from VI-CarRealTime 18.0 there are two channels representing the steering wheel torque:</p>
<p style="text-align: justify; text-indent: 0px; padding: 0px 0px 0px 20px; margin: 7px 0px 0px 48px;"><span style="font-style:italic; font-size:10pt; font-family: 'Arial';color:#000000;display:inline-block;width:20px;margin-left:-20px">1.</span><span class="f_NormalIndentParameters" style="font-style: italic;">VI_CarRealTime.Outputs.Steering_System.Steering_Wheel_Torque</span></p><p style="text-align: justify; text-indent: 0px; padding: 0px 0px 0px 20px; margin: 7px 0px 0px 48px;"><span style="font-style:italic; font-size:10pt; font-family: 'Arial';color:#000000;display:inline-block;width:20px;margin-left:-20px">2.</span><span class="f_NormalIndentParameters" style="font-style: italic;">VI_CarRealTime.Outputs.Steering_System.DriveSim_Steering_Feedback_Torque</span></p><p class="p_Normal">&nbsp;</p>
<p class="p_Normal">The torque value applied to the steering motor is the second one. When the simulated vehicle model uses a <span style="font-style: italic;">Standard Steering System</span> these two channels are equal, while they are different when a<span style="font-style: italic;"> Rack-Pinion Steering</span> model is used.</p>
<p class="p_Normal">The first channel represents the torque the driver is applying to the steering wheel.</p>
<p class="p_Normal">The second channels is a signal which can be used to generate a steering wheel torque feedback on a driving simulator.</p>
<p class="p_Normal">&nbsp;</p>
<p class="p_Normal">The difference between the two channels is that the second one does not contain the following torque contributions:</p>
<p style="text-align: justify; text-indent: 0px; padding: 0px 0px 0px 13px; margin: 7px 0px 0px 48px;"><span style="font-size:10pt; font-family: 'Arial Unicode MS','Lucida Sans Unicode','Arial';color:#000000;display:inline-block;width:13px;margin-left:-13px">&#8226;</span><span class="f_NormalIndentParameters">torque given by the column friction;</span></p><p style="text-align: justify; text-indent: 0px; padding: 0px 0px 0px 13px; margin: 7px 0px 0px 48px;"><span style="font-size:10pt; font-family: 'Arial Unicode MS','Lucida Sans Unicode','Arial';color:#000000;display:inline-block;width:13px;margin-left:-13px">&#8226;</span><span class="f_NormalIndentParameters">inertial torque given by all the inertia elements starting from the steering wheel down to the first flexible element. </span></p><p class="p_Normal">&nbsp;</p>
<p class="p_Normal">In the case where the upper column is flexible or the torsion bar is located on the upper column, the inertia which is neglected in VI_CarRealTime.Outputs.Steering_System.DriveSim_Steering_Feedback_Torque is given by the steering wheel inertia and half of the upper column inertia. In all other cases the steering wheel inertia, the upper column inertia, the intermediate column inertia, and half of the lower column inertia are neglected.</p>
<p class="p_Normal">&nbsp;</p>
<p class="p_Normal">When using VI-CarRealTime on a real simulator the steering device will have its own inertia, friction, and damping. In VI-DriveSim the user can specify the values of these parameters such that only the required effects are applied. For example let us consider the inertial torque and assume that:</p>
<p style="text-align: justify; text-indent: 0px; padding: 0px 0px 0px 13px; margin: 7px 0px 0px 48px;"><span style="font-size:10pt; font-family: 'Arial Unicode MS','Lucida Sans Unicode','Arial';color:#000000;display:inline-block;width:13px;margin-left:-13px">&#8226;</span><span class="f_NormalIndentParameters">the steering device on the simulator has an inertia of 0.039 Kg*m^2. This quantity should be specified under Action Feedback -&gt; Steer Feedback Motor -&gt; Cockpit parameters -&gt; Inertia coeff;</span></p><p style="text-align: justify; text-indent: 0px; padding: 0px 0px 0px 13px; margin: 7px 0px 0px 48px;"><span style="font-size:10pt; font-family: 'Arial Unicode MS','Lucida Sans Unicode','Arial';color:#000000;display:inline-block;width:13px;margin-left:-13px">&#8226;</span><span class="f_NormalIndentParameters">the inertial torque which is neglected in the channel VI_CarRealTime.Outputs.Steering_System.DriveSim_Steering_Feedback_Torque corresponds to an inertia of 0.042 kg*m^2.</span></p><p class="p_Normal">&nbsp;</p>
<p class="p_Normal">This quantity will be copied automatically by VI-DriveSim under <span style="font-style: italic;">Action Feedback -&gt; Steer Feedback Motor -&gt; Simulations parameters -&gt; Inertia coeff</span> if the configuration parameter <span style="font-style: italic;">VIDRIVESIM_ADVSTEER_AUTOSET=1 </span>of the <span style="font-style: italic;">vicrt</span> module in the <span style="font-style: italic;">Configuration</span> tab, otherwise it should be set manually.</p>
<p class="p_Normal">VI-DriveSim will calculate the difference between this two values (0.042 - 0.039 = 0.003 kg*m^2) and communicate it to the motor drive such that only this amount of inertia will be simulated and added to the simulated torque.</p>
<p class="p_Normal">An equivalent procedure is used for friction and damping. Only positive values of inertia, friction and damping can be simulated and added by the motor drive.</p>
<p class="p_Normal">It must be kept in mind that to have a realistic steering wheel feel on the simulator it is important that the real steering wheel matches as close as possible the one which is found on the simulated vehicle.</p>
<p class="p_Normal">&nbsp;</p>

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